Behringer high-precision digital 24-bit/96 kHz EQ/RTA mastering processor DEQ2496 - Manual (Page 15)

15 ULTRACURVE PRO DEQ2496 User Manual
Please observe a few points to achieve optimum results:
Before you start equalizing the frequency response of your audio system,
we recommend that you listen to “uncorrected” music and speech material,
which has proven useful in practice: If distortion occurs, it is liable to be caused
by the system and should be eliminated there.
The setup of the speaker stacks is also important. No equalizer can substantially
improve a sound that is “muddied” by reflections from the ceiling and the walls
of the room. Often, experiments with the speaker setup and orientation allow for
dramatic improvements.
In a multi-way system you should also eliminate run-time and phase differences
before equalizing the system (our digital frequency crossover ULTRADRIVE PRO
DCX2496 provides all functions required for this purpose).
Now it’s the turn of the DEQ2496. The automatic analyzing routine (AEQ)
helps you find an acceptable basic setting. Make sure that the measurement
microphone is positioned correctly. It should be located in the direct field of
radiation of the system, and any negative acoustic circumstances should be
eliminated. It is of no use to place the microphone behind a curtain, less than
one meter away from side or rear walls, or on an open balcony, as this would
deteriorate the measuring results. Background noise must be at least 12 dB
below the measuring level to ensure valid measurements.
Once the system has been analyzed automatically with the AEQ, the resulting
basic setting allows you to fine-tune the system.
Please note:
A linear frequency response curve is not ideal for all applications. For example,
for speech transmission intelligibility is the key. As a consequence, the curve
should be increasingly flat towards the low-frequency range, because here the
human voice produces nothing but interference (rumble noise).
Extremely low and high frequencies are usually reproduced with considerably
less energy. There is no point in “forcing” a small full-range speaker box to
reproduce a frequency response well below 50 Hz. The best result you can get is
the need for more power—and more money for repairing the speakers.
◊ Whenever you set up your audio system, please always take account of
its physical limits.
If time permits, make several measurements with the measurement microphone
at different positions.
XENYX 2222FX
ULTRACURVE PRO DEQ2496
B1520 PRO
Stage
Position 1
B1520 PRO
Position 3
Position 5 Position 6
Position 2
Position 4
Fig. 4.2: Positioning the measurement microphone
Positions 1 and 3 are approx. 1 m on-axis in front of the speakers, about half
the distance between midrange and tweeter systems. These measurements are
used to verify the functioning of all loudspeakers. Position 2 is located about
2 m in front of the center of the stage. The measurement should yield roughly
the same result above 250 Hz as the measurements made at positions 1 and 3.
Below 250 Hz, the summing of the low-frequency range should result in a level
boost of approx. 3 dB.
Position 4 is located directly in front of the FOH mixing console. The curve
measured here should be the same as at position 2, however, with a lower level
due to the greater distance.
Positions 5 and 6 are on-axis again, this time, however about 1 meter before
the rear wall of the room. These measurements will reveal any problems with
reflections or stationary waves.
Please store and subsequently compare the resulting equalizer curves.
Major differences between the stored settings are most liably caused by phase
errors in the system or problems with the room acoustics. If you cannot eliminate
these problems, you have no other choice but to find the best compromise
possible. A comparison with the stored equalizer curves will be very helpful.
Once the system has been set up as precisely as possible to reproduce the
desired transmission curve, you should walk around in the listening area to get
an impression of how the system sounds at the various positions. Remember to
make a break between your listening tests and to use different music or speech
programs to get a feel for the system’s sound and the room acoustics.
Good equalizer settings need both time and patience! If extreme settings are
required to achieve a usable frequency response, this should warn you of some
serious problems either in the system or the room acoustics.
Equalizers cannot solve the problems caused by poor audio systems, but can be
very useful and efficient tools for musical fine-tuning. This, in turn, allows for
often surprising improvements in terms of acoustic transparency and the overall
sound quality of sound reinforcement systems.